Catheter device having a catheter and an actuation device

ABSTRACT

The invention relates to a catheter device, having a catheter (1), an actuation device (8) at a first end of the catheter and also a mechanical transmission element (9, 10) for transmitting a movement along the catheter to the actuation device, the actuation device having a coupling element (14) which is connected to the transmission element (9, 10) and can be actuated by the latter relative to the longitudinal direction of the catheter in a first degree of freedom, and also a conversion element (15) which can be actuated by the coupling element and which converts the actuation movement at least partially into a movement in a second degree of freedom. As a result, a combined movement at the distal end of the catheter can be produced particularly simply for compression and release of a functional element.

The invention resides in the field of medical equipment and can be usedadvantageously in particular in operations on the human or animal body.

The invention relates in detail to a catheter device which has acatheter to be introduced and also additional elements which ensureoptimised usability of the catheter device.

A catheter of this type can be introduced through an entry opening intoa naturally occurring vessel of the body or a tube, for example a bloodvessel or a ureter, in order to perform specific desired functions in aminimally invasive manner. At the end of the catheter a functionalelement which allows specific operations by remote control can beprovided.

The problem often resides in bringing firstly the functional element bymeans of the catheter to the correct place in the body without damagingbody regions en route beyond an acceptable extent. For this purpose, thefunctional element can be either covered or deformed during introductionsuch that the introduction is made possible without damage or at leastmade easier.

A number of catheter devices is already known from the state of the art.

An intracardial pump device with a catheter is known from the Germanpatent specification DE 103 36 902 B3, which catheter carries a pump inits end region. This can basically have a larger diameter, to a limiteddegree, than the catheter but the pump must be introduced and removedsurgically in the case of too large a diameter since it is basicallyinvariable in diameter.

From the German patent specification DE 100 59 714 C1, a pump is knownfor introduction into a blood vessel of a body, the pump discharging atthe distal end into a cannula, the diameter of which is variable. Forexample, the cannula is situated during introduction into the bloodvessel in a compressed state which is assumed, as a function of thetemperature, in a range of low temperatures. If the cannula is insertedinto the body, then it heats to body temperature and thereby assumes asecond, expanded shape because of the shape memory of the materialthereof. The cannula can comprise for this purpose for example Nitinol,a known material with shape memory properties. Any possibilities oftransferring a cannula widened in this manner again into the compressedstate in order to be able to withdraw the pump and the catheter withoutsurgical intervention are not referred to in the mentioned document.

A catheter device with a pump is known from WO 94/05347, in which a pumphousing and possibly also the pump blades can be radially deployed byrelative longitudinal displacement of a drive shaft relative to a sleevedirectly surrounding the latter.

Against the background of the state of the art, the object is set ofproducing a catheter device by as simple and economical constructionalmeans as possible, which catheter device allows optimised introductionand removal of the catheter with as little damage as possible andthereby obtains an as large as possible clear transit channel of thecatheter.

The object is achieved according to the invention by the features ofpatent claim 1.

The invention thereby provides a catheter device, having a catheter, anactuation device at a first end of the catheter, a drive element insidethe catheter for driving the actuation device, for example the driveelement being a flexible shaft that drives a pump rotor in the actuationdevice if the actuation device is a pump and the catheter device alsohaving a mechanical transmission element for transmitting a movementalong the catheter to the actuation device, the actuation device havinga coupling element which is connected to the transmission element andcan be actuated by the latter relative to the longitudinal direction ofthe catheter in a first degree of freedom, and also a conversion elementwhich can be actuated by the coupling element and which converts theactuation movement at least partially into a movement in a second degreeof freedom.

The catheter according to the invention, which preferably entirelycomprises biocompatible material/materials, can hence be introducedthrough an opening into a body and thereupon a movement can betransmitted by the transmission element to the actuatable couplingelement. Such a movement can be effected for example in the longitudinaldirection of the catheter in the form of pushing or pulling, or in theform of a rotation about the longitudinal direction of the catheter ifthe transmission element allows transmission of a rotary movement, forexample if the transmission element is configured as a hose inside thecatheter, for example surrounding a flexible shaft or surrounding thecatheter.

The movement transmitted to the coupling element in the first degree offreedom is transmitted from the latter to a conversion element whichconverts the actuation movement into a movement in a second degree offreedom. The movement in the first degree of freedom can thereby beretained in addition for the entire movement of the conversion elementand the actuation device.

For example, the conversion element can have a link guide or a similardevice, such as for example a worm, for converting between a movement inthe longitudinal direction of the catheter and a rotary movement aboutthe longitudinal direction. In this case, for example a pulling orpushing movement along the catheter can be converted into a rotarymovement or vice versa.

Advantageously, the link guide can have a link track and a link block,at least one of these elements, in particular the link block, beingconnected rigidly to the catheter in the form of a guide pin. In thisway, in particular a pushing or pulling movement applied by cables alongthe catheter can cause a corresponding movement of the coupling elementalong the catheter, which movement for its part produces arotary-thrusting movement of the conversion element. An advantage of theinvention in this case resides in the fact that the rotary component ofthe movement need not be transmitted along the entire catheter butinstead is produced only at the end of the catheter by the conversionelement.

The rotary-thrusting movement at the end of the catheter can be usedadvantageously in that it is transmitted to a protective cap whichprotects a functional element at the end of the catheter and can beapplied particularly easily by means of the rotary-thrusting movement.

If the transition element is intended in particular to transmit amovement in the longitudinal direction of the catheter, then it can beconfigured as a cable, in particular in the manner of a Bowden cable, oras a group of cables which are connected to the coupling element, extendalong the catheter, in particular on the outside thereof, and can beactuated from outside after introduction of the catheter into a vessel.

The cables are advantageously guided individually on or in the catheterin a longitudinally displaceable manner, for example in that they arerecessed at least partially in the wall of the catheter.

It can also be provided that the cable or cables are guided in guidedevices on the outside of the catheter, such as for example externalrings.

If the transmission element is configured as a cable or group of cables,then these are advantageously fixed individually on a common fixingelement taking into account the longitudinal adaptations which arerequired by the given curvature of the catheter. The fixing element canbe formed for example by the cooperation of two rings, between which theindividual cables can be firmly clamped after the catheter isintroduced. The group of cables can thereafter be moved uniformly bymanipulation of the fixing element.

At the end of the catheter which is situated opposite the fixing elementand on which the transmission element is connected to the couplingelement, the latter can be configured as a bearing ring to which theconversion element is connected rotatably. It is consequently ensuredthat, in the case where the conversion element performs a rotarymovement, this is not transmitted to the coupling element and the cablesor in general the transmission element. The transmission element canhence perform purely a movement in the longitudinal direction of thecatheter.

Conversely, also the transmission element can be configured as a hose ortubular element and be designed to transmit a rotary movement about thelongitudinal direction of the catheter. In this case, the rotarymovement is transmitted to the conversion element which converts thisinto a movement in the longitudinal direction of the catheter. It isadvantageously ensured in this case that the conversion element isdisplaceable in the longitudinal direction of the catheter relative tothe coupling element, for example in that the coupling element and theconversion element are introduced one into the other in a telescopicmanner.

The catheter device can advantageously be configured such that a lock isprovided for guiding the catheter through an opening, the lock having,on the side orientated towards the actuation device, a shape whichretains the coupling element during withdrawal of the catheter andconsequently produces a rotary movement of the conversion element.

If the catheter is removed, i.e. withdrawn for example from a bloodvessel, then it should be ensured that the functional element isprotected in that for example a cap is pushed onto the functionalelement by means of the actuation device. For this purpose, it isensured by means of the lock that the transmission element also effectsa thrusting movement during withdrawal of the catheter, which movementis converted on the actuation device by the conversion device into thedesired combination movement for placing on a protective cap.

It can be ensured for this purpose that, during further withdrawal ofthe catheter, the lock is jointly removed or that, after actuation ofthe transmission element, the latter can be moved through the lock.

A particularly favourable and advantageous use of the catheter device ischaracterised by a functional element, in particular a pump, at the endof the catheter and also a protective cap which is connected to theconversion element and which receives the functional element in a firstposition of the conversion element and releases said functional elementin a second position.

If the protective cap has smaller inner dimensions than the outerdimensions of the functional element in the released position and thefunctional element can be compressed at least partially, the functionalelement can, on the one hand, be compressed by the actuation devicethrough the catheter device according to the invention when removingsaid functional element and, on the other hand, if the actuation deviceassumes its second position, the functional element can be released inorder to expand. Corresponding expansion movements can be achieved forexample by using so-called temperature memory alloys or in that forexample pump blades expand automatically into an operating state duringrotary operation of a functional element configured as a pump.

An advantageous method for introduction according to the invention of acatheter device which is configured according to the invention providesthat firstly the catheter is introduced, the actuation device beingsituated in a first position, and that thereupon the coupling elementand the conversion element are actuated by means of the transmissionelement in order to release a functional element by means of theactuation device in the second position thereof. Hence, it is ensured ina simple manner, not particularly susceptible to faults, that a cathetercan be introduced with an expandable functional element or a functionaldevice with a low risk of injury into a vessel of a patient andthereafter can be expanded in the desired manner. As a result of theconstruction according to the invention, also functional faults areminimised during removal of the catheter device.

In the following, the invention is shown and subsequently described withreference to an embodiment in a drawing with reference to severalFigures. There are thereby shown

FIG. 1 schematically, a catheter introduced into a blood vessel, the endof the catheter being situated in the volume of a ventricle,

FIG. 2 schematically, in longitudinal section, a catheter having anactuation device and a functional element,

FIG. 3 in longitudinal section, a device for fixing cables,

FIG. 4 an alternative device to that shown in FIG. 3,

FIG. 5 the actuation device enlarged in longitudinal section with a partof a functional element and also

FIG. 6 the actuation device schematically in a cross-section.

In the embodiment, the application of the invention to a catheter isdescribed in particular, which catheter carries a pump at the endthereof and can be introduced into the bloodstream of a patient.

Pumps of this type which are introduced for example into the heart of apatient and serve to convey blood for supporting the heart are basicallyknown. It is thereby also known to construct such pump structures suchthat they can be widened in diameter after introduction into theventricle.

It is sensible and essentially an application advantage of the presentinvention to provide thereby a mechanism which can release thefunctional element which, in the present case, comprises the pump sothat it is potentially widened automatically and can also compress inorder to be able to remove the functional element/the pump with thecatheter again from the body. In the interim, the entire device shouldadvantageously remain in the body and should neither damage the patientin this state nor impede the flow of blood through the catheter beyond atolerable degree.

Basically, the catheter 1 which is represented merely schematically inFIG. 1 is introduced through an incision 2 by means of a lock 3 into theblood vessel, is pushed through the latter until the end 5 of thecatheter with the functional element 6 that can be rotatably driven bythe flexible shaft 4 is positioned in the ventricle 7 and is fixed inthis state, and the actuation device 8, which will be dealt with furtheron in more detail, can be actuated in order to release the functionalelement 6 by means of a transmission element. The flexible shaft 4 maybe connected at its proximal end to a motor located outside the body.

In FIG. 2, the transmission element and also the actuation device andthe functional element are described in more detail. FIG. 2 shows inlongitudinal section a catheter 1 which is surrounded by a group ofcables 9, 10 which extend parallel to each other in the longitudinaldirection of the catheter 1 at the circumference thereof and parallel toa flexible shaft 4 if such a shaft is used for driving a functionalelement like a pump rotor at the end of the catheter. In order to guidethe cables 9, 10, these can be recessed entirely or partially in thewall of the catheter 1 moveably in the longitudinal direction or can beguided through guide devices 11, 12 in the form of openings or loops onthe circumference of the catheter. If the cables are sufficiently rigidand the guide devices 11, 12 are set sufficiently narrowly, also athrusting movement can be achieved by means of the cables in addition toa pulling movement.

On the other hand, it is conceivable as an alternative to replace thecables by a hose which surrounds the catheter 1 concentrically andlikewise can serve for transmitting pulling and thrusting movements.

For this purpose, the hose should be provided with corresponding axialcompression strength without the bending rigidity being significantlyincreased. Corresponding technologies are adequately known industriallyand already used.

Basically, also the production of the transmission element by a singlecable at the circumference of the catheter is conceivable. Thearrangement of cables on the outside of the catheter or at leastpartially in the wall of the catheter is thereby preferred, however, inparticular with a small number of cables, also guidance thereof withinthe catheter or a hose inside the catheter is basically conceivable.

The cables 9, 10 are mounted together, for example by clamping, on thefixing element 13. Hence the entirety of cables can be moved in the samedirection and to the same extent by manipulation of the fixing element13. The fixing element is dealt with below in even more detail.

In addition, a coupling element 14 which is configured there as abearing ring which is displaceable in the longitudinal direction of thecatheter is evident in FIG. 2. Cables 9, 10 are fitted on this bearingring 14 so that pulling or pushing movements of the cables aretransmitted firstly to the bearing ring 14.

On the other hand, the conversion element 15 in the form of a cylinderprovided with one or more link tracks 16 is connected to the bearingring 14. The coupling element 14 transmits pulling and thrustingmovements to the cylinder 15, in the link track of which a guide pin 17which forms a link block is guided. The cylinder 15 is consequentlyforced onto a screw-like movement track since the guide pin 17 is fixedin the catheter 1.

In order that the conversion element 15 can rotate independently of thebearing ring 14, a rotary bearing 18, for example in the form of asliding bearing, is provided between these two elements, said slidingbearing being able to transmit the thrusting and pulling forces.

If the cables 9, 10 are actuated, then a thrusting movement in thedirection of the arrow 19 is produced for the bearing ring 14 just asfor the cylinder 15 and is superimposed in addition by a rotary movementthrough the link guide in the case of the cylinder 15.

In FIG. 2, a blood pump is represented as functional element 6 at theend of the catheter 1, which blood pump is widened relative to thediameter of the catheter or of the actuation device. This is possible inthat the mentioned functional element can assume an expanded and acompressed situation, it being able to be received at least partially inthe compressed situation by a protective cap 20 at the end of theactuation element 14, 15.

If the conversion element 15 together with the protective cap 20 iswithdrawn by the cables 9, 10 in a screw-like movement, then the pump 6can widen in diameter, whilst it is compressed during a thrustingmovement of the cables 9, 10 by the screw movement of the cap 20 and isreceived at least partially in the cap.

In addition, it becomes clear by the representation of FIG. 2 that, whenremoving the catheter from the incision, the lock 30 consequently playsa special role in that the thrusting movement of the protective cap 20is introduced or ended at the latest when the bearing ring 14 strikesthe lock 3 so that the functional element is present in a completelycompressed form at least when passing through the incision.

The pump is configured in particular for the purposes ofcompressibility, the rotor blades of the pump for example being able tobe folded in and the housing being able to be collapsed, for example bythe production from a so-called temperature memory material, an alloywhich can assume different shapes at different temperatures. Anelastically compressible construction is likewise conceivable, which canbe opened up or closed merely by the force effect and/or by the effectof the conveyed fluid into the desired position.

FIG. 3 shows a fixing element 13 in the form of two conical rings 21,22, between which the cables 9, 10 can be clamped by axial compressionof the rings. Since the cables are fixed individually, lengthdifferences which are produced by curvature of the catheter and acorrespondingly different length requirement of the cables situatedradially inwards or outwards, can be compensated for. The fixing elementin this case should fix the cables after introduction of the catheter.Thereafter, the group of cables can be actuated together by means of thefixing element.

Another embodiment variant of the fixing element is represented in FIG.4, in which the cables 9, 10 can be fixed with a squeezing or bendingmovement by means of correspondingly moveable elements 23, 24.

The mode of operation of the conversion element 15 emerges from FIG. 5in more detail than from FIG. 2, a plurality of guide pins 17, 17 abeing represented there, said guide pins being mounted respectively onthe catheter 1 and being able to run in different, parallel, screw-likelink tracks 16, 16 a which are offset relative to each other.

The protective cap 20 at the end of the conversion device 15 can beintegrated in the latter or connected to the latter.

It should be mentioned in addition that a shaft 25 can be providedwithin the catheter 1, which serves to drive the pump 6 and is mountedin the pump housing 26. By means of the shaft 25, rotor blades 27, 28are actuated and blood is conveyed for example through the openings 29in the pump housing 26. According to the design of the rotor/of thepump, also an inflow towards the rotor through the openings 29 in thepump housing 26 is possible and an axial outflow or an axial inflow andoutflow.

In FIG. 6, a cross-section through the catheter in the region of theactuation device is shown, the guide pin/guide block 17 integrated inthe catheter 1 being represented. The guide pin 17 can either be cast inor glued into the catheter and/or even comprise the material of thecatheter 1 and also be configured in one piece with the catheter. Thecatheter should comprise a flexible but solid plastic material whichensures a constant cross-section of the catheter. If a hose is used astransmission element, then the latter can comprise the same material asthe catheter. If cables are used, then these must comprise ahigh-strength biocompatible material, such as for example special steel,platinum or silver wire or specific plastic materials. The cables can beprovided with a locking device in order to allow fixing at differentlengths respectively according to the present curvature of the catheteron the fixing element.

By means of the screw-like movement of the actuation device producedwith the invention, pushing a protective cap onto the functional elementis substantially facilitated already with respect to the more favourablefriction conditions. By applying a thread-like surface structure on theoutside of the functional element, i.e. in particular on the pumphousing and/or on the inside of the protective cap, the compressionmovement can in addition be facilitated.

The invention hence ensures simple and reliable actuation of anactuation device for protecting a functional element during positioningof the catheter in a sensitive region within the body of a patient.

1-18. (canceled)
 19. A catheter device, comprising: a catheter having aproximal end and a distal end; a blood pump, comprising: a rotor, and ahousing enclosing the rotor, the housing coupled to the distal end ofthe catheter; a flexible drive shaft having a proximal end and a distalend, wherein the catheter surrounds the flexible drive shaft; one ormore cables coupled to the catheter such that an axial movement of theone or more cables in relation to the catheter is converted at leastpartially into a rotational movement of one of the catheter or the oneor more cables.
 20. The catheter device of claim 19, wherein the one ormore cables are partially recessed into a wall of the catheter.
 21. Thecatheter device of claim 19, wherein the one or more cables are fullyrecessed into a wall of the catheter.
 22. The catheter of claim 20,wherein the one or more cables are moveable in a longitudinal directionwithin the wall of the catheter.
 23. The catheter device of claim 19,wherein the one or more cables are comprised of a biocompatiblematerial.
 24. The catheter device of claim 23, wherein the biocompatiblematerial is one of a steel, platinum, silver wire, or plastic material.25. The catheter device of claim 19, wherein the one or more cables isconfigured to move independently in respect to a movement of thecatheter in a longitudinal direction.
 26. The catheter device of claim25, wherein the fixing element comprises two conical rings configured tofix the one or more cables to the catheter.
 27. The catheter device ofclaim 26, wherein the two conical rings are configured to fix each cablein the one or more cables individually to the catheter.
 28. The catheterdevice of claim 26, wherein the conical rings are configured to clampthe one or more cables by axial compression of the conical rings. 29.The catheter device of claim 19, further comprising at least one guidedevice attached to an outer surface of the catheter.
 30. The catheterdevice of claim 29, wherein the at least one guide device comprises aloop attached to the outer surface of the catheter.
 31. The catheterdevice of claim 30, wherein the one or more cables are guided throughthe loop of the at least one guide device attached to the outer surfaceof the catheter.
 32. The catheter device of claim 25, further comprisingtwo moveable rings configured to fix the one or more cables to thecatheter.
 33. The catheter device of claim 32, wherein the two moveablerings are configured to fix the one or more cables to the catheter via abending movement.
 34. The catheter device of claim 32, wherein the twomoveable rings are configured to fix the one or more cables to thecatheter via a squeezing movement.
 35. The catheter device of claim 25,wherein the catheter is configured to extend through a vessel of apatient, and wherein the one or more cables are configured to be fixedto the catheter after the catheter is positioned in the vessel of thepatient.
 36. The catheter device of claim 19, wherein the housingcomprises an elastically compressible material.
 37. The catheter deviceof claim 19, wherein the housing comprises a memory alloy.
 38. Thecatheter device of claim 19, wherein the memory alloy is Nitinol.